Amide-glyoxal-formaldehyde reaction product and shrinkproofing cellulose textile fibers therewith



Patented Nov. 6, 1 951 AltflDE-GLYOXAL-FORMALDEHYDE REAC- TION PRODUCT AND SHRINKPROOFING CELLULOSE TEXTILE FIBERS THERE- WITH Ren Lon Lehmann, Paris, and Josef Lintner, La Garenne Colombes, France, assignors to Bozel-Maletra Societe Industrielle de Produits Chimiques, Paris, France, a corporation of France No Drawing. Application November 3, 1948, Serial No. 585156. In France April 26, 1948 9 Claims.

It is known that it is possible to reduce substantially the swelling power and the alkaline solubility of cellulose by subjecting it to the action of formaldehyde or glyoxal. It has already been attempted in the art to use such methods for manufacturing unshrinkable textile fabrics.

The use of the two products mentioned above gives rise however to many drawbacks. Formaldehyde is very volatile and when used for enhancing the qualities of cellulose, it causes serious troubles from the point of view of the heating conditions in the workplaces; besides, the volatility of formaldehyde varies considerably with the drying conditions and, in practice, it has heretofore been impossible to obtain definite concentrations of formaldehyde on the fabrics treated with formaldehyde after drying. is the reason why, up to the present time, all attempts to obtain constant effects on a fabric with formaldehyde, even if it were on a single fabric strip have proved unsuccessful. Therefore the treatment of cellulose with formaldehyde with a view to manufacturing unshrinkable fabrics has been given up by the manufacturing firms. It has been attempted to substitute glyoxal for formaldehyde (according to the socalled Sanforset method) because glyoxal does not have the drawback of being volatile which is inherent in formaldehyde. The merit of glyoxal for enhancing the qualities of textile fabrics, however, has also turned out to be very moderate: indeed the reactivity of glyoxal with respect to the hydroxyl groups of cellulose is materially lower than that of formaldehyde, which implies higher reaction temperatures and therefore a far stronger treatment of the cellulose fibre. On the other hand, glyoxal is chemically far less stable than formaldehyde, particularly in an alkaline medium, which is a further drawack.

Now the applicants have discovered that by condensing an amide such as urea, melamine and oxamide, in an acid medium with such an amount of glyoxal that it fixes only a portion, preferably not exceeding 50%, of the reactive nitrogen of' the amide and by then treating the condensation products thus obtained in an alkaline medium with an amount of formaldehyde at least equal to the amount, stoichionietrically to fix the remaining reactive nitrogen, it is very easy to obtain water soluble products containing in dry weight up to 45% of formaldehyde in combined form and having the following remarkable properties resulting from the presence of This the glyoxal in the molecule: although the formaldehyde is combined therein as a methylol group fixed on the nitrogen and although the said products are stable, non-volatile and not entrained by aqueous vapour, nevertheless they still give all chemical reactions of free formaldehyde without any risk of self-condensation into products having a higher molecular weight which would be difiicultly soluble in water. In particular the said methylols very easily form acetals with the hydroxyl groups of cellulose, even in the presence of water and even under the action of only slightly acid catalysts, such as ammonium nitrate.

Due to these properties, the products obtained according to the invention are remarkably well adapted to improving the qualities of cellulose, particularly with a view to obtaining an unshrinkable fibre and one not likely to swell. Indeed:

1. The high reactivity of the products permits treatment of the fibre under very moderate conditions thus avoiding any degradation of the cellulose. Technically, the necessary treatment temperatures range from 110 C. to 120 0.; these temperatures may therefore be reached easily in the usual desiccators.

2. The non-volatility of the said products together with their stability and their good solubility in water makes it possible to obtain a uniform effect when treating the fibre. Moreover during the drying operation working conditions are satisfactory since no unpleasant vapour is emitted.

3. The said condensation products have a high stability, particularly in an alkaline medium, as distinguished from. glyoxal; this is the reason why the effects obtained on fabrics with the said products are substantially unaffected by known washing methods.

4. The good solubility in water of the products makes it possible to remove easily and completely the excess'of condensation product which has not been used in the reaction with the fibre. Subsequent modifications of the fibre, such as its turning yellow or its transformation into brittle fibre are thus avoided.

5. The products are odourless and have not the unpleasant physiological properties of free asrans tion is then alcalinized and condensed with a solution at 30-40% of formaldehyde, at a temperature preferably ranging from 50 to 100 C.

When subsequently used for treating textile materials the solution thus obtained is diluted with water, added with a catalyst such as ammonium nitrate; the textile product or fabric is then impregnated with the solution obtained. Finally after having been wrung out and dried the product is heated preferably at 1l0120 C. for about 15 minutes.

The textile product thus obtained has a swelling power which is considerably lowered as compared with the original product; it has become practically unshrinkable; its strength against friction in the wet state has been considerably increased.

Therefore a far higher resistance of the fabrics to known washing methods is thus obtained.

When fibres are liable to become brittle, it is advisable to effect the treatment in the presence of a small amount of a water-soluble polyvalent alcohol such as glycerol, ethylene glycol or 1.6 hexanediol.

Two examples are given hereunder as specific illustrations of possible embodiments of the method according to the invention.

Example 1 1.6 kg. urea is dissolved i 5.8 kg. of a diluted aqueous glyoxal solution; t e solution thus obtained is then acidified, for example by means of a small amount of highly concentrated hydrochloric acid and the mixture is heated to ebullition. As soon as the glyoxal is combined, the product is allowed to cool down. The white precipitate of glyoxal diurea is segregated and then mixed with an alkaline aqueous solution of formaldehyde at 30% in which a small amount of glycerol has been previously dissolved. Then after heating to ebullition and acidifying, the boiling is continued until the formaldehyde and glycerol are combined. The solution thus obtained is neutralized, then diluted with water down to a 60 g. per litre content in dry material. 20 g. ammonium nitrate per litre are dissolved thereon, then the cellulose fabric to be treated is immersed in the said solution while stirring, for a few minutes. The fabric is then wrung out until there remain on the fibre onl a, weight of solution equal to the weight of the original dry fabric. The fabric is then dried at 80-90 C. and finally the dry fabric is further heated for about 15 minutes to about 120 C.

Under the conditions of this example, if the textile material to be treated is for instance a regenerated cellulose fabric, the swelling power is reduced by the treatment, for example, from the original value of 100, to a value of 53, which is near the optimum value; the rate of shrinking by washing drops for example from 15% origi nally to about 0.5% after treating. The resistance to friction of the wet fabric is improved for example by about 30%.

Example 2 2.52 kg. melamine are introduced into 5.8 kg. of a diluted aqueous glyoxal solution; the resulting product is then acidified, for example by means of a small amount of highly concentrated hydrochloric acid and the mixture is heated to ebullition. As soon as the glyoxal is combined, the mixture is allowed to cool down. It is then mixed with an alkaline aqueous solution of formaldehyde at 30% and the product thus obtained 4 is heated to ebullion until the formaldehyde is combined. Finally the product is neutralized, for example by means of hydrochloric acid or nitric acid.

The treatment of the fibre may then be eifected according to the mode of operation mentioned in Example 1.

What we claim is:

1. A method for preparing products for enhancing the properties of textile materials, consisting in heat condensing an amide selected from the group consisting of urea. melamine and oxamide, with glyoxal in an acid medium, the amount of glyoxal being less than the stoichiometrical amount, whereby only a portion of the reactive nitrogen of said amide is fixed, and then heat condensing the product thus formed with formaldehye in an alkaline medium. the amount of formaldehyde being at least equal to the stoichiometrical amount. whereby the remaining reacive nitrogen is fixed.

2. A method for preparing products for enhancing the properties of textile materials, consisting in heat condensing an amide selected from the group consisting of urea, melamine and oxamide, with glyoxal in an acid medium. the amount of glyoxal being almost equal to 50 per cent of the stoichiometrical amount. whereby a portion of the reactive nitrogen of said amide which is almost equal to 50 per cent is fixed, and then heat condensing the product thus formed with formaldehyde in an alkaline medium, the amount of formaldehyde being at least equal to the stoichiometrical amount, whereby the remaining reactive nitrogen is fixed.

3. A method for preparing products for enhancing the properties of textile materials, consisting in heating an amide selected from the group consisting of urea, melamine and oxamide, with glyoxal in an acid aqueous medium, the amount of glyoxal being less than the stoichiometrical amount required for reaction with all of the amino groups of said amide, whereby only a portion of said nitrogen is fixed, alkalinizing the product thus formed and heating said last product in the presence of formaldehyde at least in a stoichiometrical amount with respect to the unreacted reactive nitrogen, whereby said nitrogen is fixed on the formaldehyde.

4. A method for preparing products for enhancing the properties of textile materials, consisting in heating an amide selected from the group consisting of urea, melamine and oxamide, with glyoxal in an acid aqueous medium, the amount of glyoxal being less than the stoichiometrical amount required for recreation with all of the amino groups of said amide. whereby only a portion of said nitrogen is fixed, alkalinizing the product thus formed and heating said last product at a temperature between 50 and C. in the presence of formaldehyde at least in a stoichiometrical amount with respect to the unreacted reactive nitrogen, whereby said nitrogen is fixed on the formaldehyde.

5. A method for preparing products for enhancing the properties of textile materials, consisting in heat condensing an amide selected from the group consisting of urea, melamine and oxamide, with glyoxal in an acid medium, the amount of glyoxal being less than the stoichiometrical amount, whereby only a portion of the reactive nitrogen of said amide is fixed, and then heat condensing the product thus formed with formaldehyde in an alkaline medium, the amount of formaldehyde being equal to the stoichiometrical amount. whereby there remains no free formaldehyde.

6. A method for preparing products for enhancing the properties of textile materials, consisting in heat condensing an amide selected from the group consisting of urea, melamine and oxamide, with glyoxal in an acid medium, the amount of glyoxal being less than the stoichio metrical amount, whereby onlyta portion of the reactive nitrogen of said amide is fixed, then heat condensing the product thus formed with formaldehyde in an alkaline medium, the amount of formaldehyde being at least equal .to the stoichiometrical amount, whereby, the remaining reactive nitrogen is fixed, and then neutralizing the product thus obtained with an acid.

7. A method ior enhancing the properties 01' cellulose fibers, in particular with a view to eliminating their tendency to shrink and to swell when wet, consisting in impregnating said fibers with an aqueous solution containing, together with an acid catalyst, the compound produced by the process of claim 1, then wringing and drying said fibers and finally heating said dry fibers to a temperature of 110 C. to 120 C.

REFERENCES CITED 10 The following references are of record in the file 01 this patent:

UNITED STATES PATENTS Number Name Date 15 2,301,676 Balle et a1 Nov. 10, 1942 2,369,948 DAlelio Feb. 20, 1945 2,388,086 Rust Oct. 30, 1945 2,412,832 Pfeifer et al Dec. 17, 1946 00 FOREIGN PATENTS Number Country Date 458,877 Great Britain Dec. 29, 1936 463,300 Great Britain Mar. 22, 1937 484,691 Great Britain Aug. 4, 1936 25 510,199 Great Britain July 28, 1939 

1. A METHOD FOR PREPARING PRODUCTS FOR ENHANCING THE PROPERTIES OF TEXTILE MATERIALS, CONSISTING IN HEAT CONDENSING AN AMIDE SELECTED FROM THE GROUP CONSISTING OF UREA, MELAMINE AND OXAMIDE, WITH GLYOXAL IN AN ACID MEDIUM, THE AMOUNT OF GLYOXAL BEING LESS THAN THE STOICHIOMETRICAL AMOUNT, WHEREBY ONLY A PORTION OF THE REACTIVE NITROGEN OF SAID AMIDE IS FIXED, AND THEN HEAT CONDENSING THE PRODUCT THUS FORMED WITH FORMALDEHYE IN AN ALKALINE MEDIUM, THE AMOUNT OF FORMALDEHYDE BEING AT LEAST EQUAL TO THE STOICHIOMETICAL AMOUNT, WHEREBY THE REMAINING REACIVE NITROGEN IS FIXED.
 7. A METHOD FOR ENHANCING THE PROPERTIES OF CELLULOSE FIBERS, IN PARTICULAR WITH A VIEW TO ELIMINATING THEIR TENDENCY TO SHRINK AND TO SWELL WHEN WET, CONSISTING IN IMPREGNATING SAID FIBERS WITH AN AQUEOUS SOLUTION CONTAINING, TOGETHER WITH AN ACID CATALYST, THE COMPOUND PRODUCED BY THE PROCESS OF CLAIM 1, THEN WRINGING AND DRYING SAID FIBERS AND FINALLY HEATING SAID DRY FIBERS TO A TEMPERATURE OF 110* C. TO 120* C. 